<!doctype html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>转动的圆环</title>
	<style>
	.demo{
            width:250px;
            height:250px;
            border:50px solid blue;
            border-left-color:#ccc;
            border-right-color:#ccc;
            border-top-color:#ccc;
            margin:100px;
            border-radius: 50%;/*圆角*/
            -webkit-animation:circle 1s infinite linear; 
	}
	@-webkit-keyframes circle{
				0% {transform:rotate(0deg);}
				100% {transform:rotate(-360deg);}
	}
	</style>
</head>
<body>
	<div class="demo"></div>
</body>
</html>